Motor-driven push-button tuner



Aug. 29, 1950 P. WARE ErAL Daman Pusxu'rrou TUNER Filed Jan. 11. 1947 3 Sheets-Sheet l' ATTQENY Aug. 29, 1950 P, WARE TAL 2,520,749

Y UTOR-DRIVEN PUSHBUTTON TUNER Filed Jan. 11. 1947 3 Sheets-Sheet 2 ATTGRNY ug. 29, 1950 P. WARE ErAL Moran-mim: Pusiu'rrou TUNER 3 Sheets-Sheet 3 Filed Jan. 11, 1947 INVENTORS ATTORNEY Patented Aug. 29, 1950 MOTOR-DRIVEN PUSH-BUTTON TUNER Paul Ware, Pompton Plains, and Herbert Bernard, Belleville, N. J., assignors to Allen B. Du Mont Laboratories, Inc., Passaic, N. J., a corporation of Delaware Application January 11, 1947, Serial No. 721,634

12 Claims.

This invention relates to a motor driven push button selector for predetermined positions of a variable element.

One of the objects of the invention is to adapt push button selection to the type of device that requires many turns of its rotor to cover its very wide range. of settings in contrast to the 180 range of the capacitative tuning element of the usual radio receiver. With this invention this can be accomplished with a very high degree of accuracy by means of push buttons. The tuning element is caused to stop at or very close to predetermined positions consistently by pushing corresponding buttons.

Another 'object of the invention is to accomplish this tuning with a device lthat is not too heavy, bulky or difficult to manufacture or adjust, and is durable in use.

These and other objects will be apparent to those skilled in the art. The invention will be particularly described in an embodiment in which a motor driven push button tuner fora high frequency wide band radio set is used.

The invention may be-understood from the description in connection with the accompanying drawings, in which:

Fig. 1 is a plan view ofthe device with three tuning units, one of these units and the cam shaft being partly broken away.

Fig. 2 is a section along line 2-.2 of Fig. 1. partially schematic.

Fig. 3 is a detailed view of part of Fig. 2 at a later stage of the operative cycle.

Fig. 4 is a similar view showing parts later in the operative cycle.

Fig. 5 is a rear elevation view of the motor side of the unit.

Fig. 6 is a section along line 6-6 of Fig. 4.

Fig. 7 is a plan view partially in section of the motor to show the brake mechanism.

Fig. 8 is a side view to show a reversing switch that is used with the device.

The inner end of each lever I rests upon stop 2a on casing 2 (Fig. 2). An elongated latch bar 'I extends across the inner end of all the levers I. This bar is pivoted on pins 8 and is .prevented from coming too far forward by"an`adjustable stop 8' which strikes the back side of ycasing 2. The bar'l is turned clockwise on pivots 9 by a spring 'I'. A threaded or adjustable pin 8' is mounted on plate 1. The inner end ofeach of two levers 9 is pivoted on shaft I0 in casing 2 near opposite sides of this casing.. The rear end of each lever 9 is urged upwardly by spring 9' that has its upper end attached to a support 9" on the back side of casing 2 as shown invFig. 2.

The inner end of each one of the levers I is also adapted to strike an elongated lever barv II that is pivoted on pins I2 at oppositefsides of casing 2. The lever bar II is adapted to contact with the lower end of a lever arm I3 (Figs. 3 and 4) that is pivoted on pin I4 by a sleeve I4' of insulating material. Arm I3 carries a switch` arm contact I5 that is adapted to make and break contact with a switch contact I6 that is attached to pin I4. Contact I6 is urged downwardlyby spring I6' (Fig. 2). The movement of arm` I3 is retarded by a time delay mechanismv I1 and the spring I5'. The lever bar I'I is kept in contact with the lever arm I3 by the spring I3.

The switch contacts I5 and I6 control the current that is supplied to the motor I8 (Figi). The shaft I9 of this motor is connectedthrough gears 20, 2I, 22 and 23 tothe shaft 24 nof the rotor of the tuning elements 25 through the slip clutch 23', v

The shaft 24 is connected to the shaft 2lik by gears 21 and 28 (Fig. l). This shaft 26 carries pairs of cams 29 and 30 that are clamped thereon by bolts 30' (Fig. 2). Cam 30 depresses the corresponding pawl 4 and is stopped by pawl 5, or the reverse depending upon the directionof rotation of the cam shaft 26. Each cam 29 strikes the corresponding roller 6 when the inner end'of itslever I is up, and thus opens the switch I5-I8. y

The motor I8 is prevented from rotating by the brake mechanism shown in Fig. ..7 when the power is off and is permitted rto rotate kfreely when the power is on` This brake `mechanism consists of spring 3| which acts onthe motor lshaft I9 to push it longitudinally and move the lever 32 that is pivoted on pin 33yandhasa hole 34 in which shaft I9 binds. When currentfows in the field coils 35 of motor I8 its armature 36 is moved from dotted line to full line` position thus releasing shaft I9 from the binding action of lever 32.

The time delay mechanism I 1 (Figs. 2, 3 and 4) consists of the gears 31, 38, 39, and 4I which 3 areactuatedbytheratchetnthatis bytheleversystemJlJlfromiever 'l'his gear train operates vane 4I against resistancetodelayopeningoftheswitchoontacts II and it.

The reversing switch 48 is operated by the cam41 (l"ig.8) whichisattachedtctheshaft 2landsopositionedonitastooperatethis double pole double throw switch 4I.

The operation of the device is as follows:

One of the levers I is depressed according to the station to which the tuning elements are to betuned. Thisraisesstops4andlinwthepath ofeamfl andalsoraisestherollerl intothe path of cam 2l. The innerend of this lever I pushesbacklatchbar1thusturningituntilthis lever clears this bar. -The spring 1' then pulls the latch bar 1 forward under the lever I thus holding it in position as shown in Figs. 3 and 4. 'I'he adjustable pin i' prevents the latch bar 1 from turning too far clockwise because it is stopped by striking the casing 2. 'I'he end of lever I also turns a lever bar .II on pivot I2. This bar iI strikes andturns lever I2 on shaft I4 so that the switch contact I5 carried by lever Il is brought into contact with stationary contact It mounted on shaft I4 thus closing this switch. Closing the switch contacts Il and Il causes current to flow fromra source of power through the windings of the motor Il through leads, not shown. This motor Il then starts and its shaft i! drives the tuning shaft-24 (Fig. 1) which turns the rotor of tuner 25 through a gear train consisting of the gears 2l, 2i, 22 and 22. 'I'he cam shaft 2i is driven by the tuning shaft 24 through the one to ten ratio gears 21 y' 24 is held in position due to the slip clutch 22'.

At the same time that the cam 3l depresses pawl 4 the cam 29 rides up on the rollert thus depressing the rearend` ofthe lever I as shown in Fig. 4. The rear tip of lever I then presses down the lever bar 1 against the action of spring l', (Fig. 2) thus causing the lever I to turn on pivot I and change its position from that shown in Fig. 3, tilted somewhat upwardly, to that shown in Fig. 4, tilted somewhat downwardly. 'I'his removes the support from lever bar Il, but this lever II is delayed from being pulled down by the spring 1' and breaking 'the contact at switch points IS-IB because of the action of the time delay mechanism I1 (Figs. 2 and 4) operating through the lever system 42, 44 and 4l. This time delay mechanism consists of the ratchet 42 and the gear train 31, Il, ll, 4l and 4I and the vane 4t. 'I'his gear train and vane cause delay in the movement of lever il that would otherwise open the switch points Il and I 6 and stop the motor Il too soon.

When thelever Il nnally moves downwardly sumciently to permit the switch points Il and IC to open the motor I2 stops promptly due to an additional braking action on this motor which is caused by the action o f the spring 3| (Fig. 7)

While the motor I8 is operating. current thrcughtheiieldcoilscausesasolenoidaction onthearmaturelithatismmmtedsoalto permit free axial movement. This action holds thearnmtureinthepositionshownbysolidlines inm.7againstthepressureofspringll. In thispositionthebracketnisatrishtlnl tothearmatureaxlelandpermitsittoturn freely in the hole 34. However, when the current ceases to flow through the windings. there is no solenoid action to keep the amature Il in,

. this position and the spring 3| forces it into the position shown by dotted lines in Fig. '1. In this position the bracket I2 is Ano longer at right anlestotheaxle andtheshaft therefore binds against the sides of the hole 8l preventing the motor from turning.

The cam 41 (Fig. 8) is located upon the cam shaft 26 of gear 2l -in such a position that this cam shaft cannot turn a full revolution without the cam 41 engaging the arm of the toggle switch 4I and reversing the direction of rotation of the motor. 'I'he result is that regardless of the respective positions of the desired stations along the travel of the tuner units they can always be reached. If the device is in a position where 1f required to continue turning in the direction determined by the position of the reversal switch' 4l the end of travel of the tuning unit would be reached before the desired station is reached, the revolution of the cam shaft 2| would be completed at the point where the tuner could no longer move and the cam 41 would engage the arm of the reversing switch 48 and reverse the motor and so approach the desired station from the opposite direction. The device will operate satisfactorily with only one pawl 4 or 4 on each lever and without a roller I.

When any other lever I is depressed its load end in rising pushes the latch bar 1 backward and releases the flrstlever whereupon its spring 3a (Fig. 2) returns it to its original position. This sets the mechanism for the start of a new cycle and tunes to the corresponding station.

While this invention has been described with reference to its embodiment as a radio tuning device it may also be used for selecting and positioning other devices. Y

What is claimed is: 1. In a 'device of the character described, a

motor, a shaft driven by said motor, said shaft having a plurality of axially and circumfer- Yentially spaced radially extending cams thereon.

a device to o'pen a circuit to said motor coxn-V prising a cam, and a lever, and means comprising pivoted pawis carried by said lever to stop said shaft 4at predetermined positions.

I Said Shaft 3.`In a device of the character described, a'

motor, means to brake said motor when current through it is cut oil, a shaft driven by said motor,

having a plurality of axially and circumferentially spaced radially extending cams thereon, a device to open and close a circuit to said motor comprising a lever, and means comprising pivoted pawls carried by said lever to plurality of pivoted levers each carrying pivoted pawls and stops therefor and springs which urge said pawls toward said stops on one side thereof and a roller on the other side thereof.

5. In 'a device of the character described, a plurality of pivoted levers each carrying pivoted pawls and stops therefor and springs which urge said pawls toward said stops on one side thereof and a roller on the other side thereof, avshaft transverse to said levers and cams on said shaft adapted to stop said shaft where said cams strike said stops.

6. In a device of the character described, a plurality of pivoted levers, each carrying pivoted pawls and stops therefor and springs which urge said pawls toward said stops on one side thereof and a roller on the other side thereof, a shaft, transverse to said levers, and cams on said shaft adapted to stop said shaft where said cams strike said stops, a. cam on said shaft adapted to contact with said roller to depress the corresponding lever.

7. In a device of the character described, a

. plurality of levers each carrying a roller on one side and two pawls on the other side thereof, a shaft located transversely to said levers, two cams carried by said shaft for each lever, one of said cams being adapted to strike said pawls and the other one having a rounded end to strikesaid roller and depress the corresponding lever and springs mounted on said levers urging said pawls toward said cams.

8. In a device of the character described, a plurality of levers each carrying a roller on one side and two pawls on the other side thereof, a shaft located transversely to said levers, two cams carried by said shaft for each lever, one of said cams being adapted to strike said pawls and the other one having a rounded end to strike said roher and depress the corresponding lever and a switch adapted to be closed by any one of said 9. In a device of the character described, a plurality of levers each carrying a roller on one side and two pawls -on the other side thereof, a

shaft located transversely to said levers, two` cams carried by said'shaft for each lever, one of 'said cams being adapted to` strike said pawls and the other one having a rounded end to strike said miler and depress the corresponding lever, a

switchadaptedtobeclosedbyanyoneofsaid levers and adelay mechnismto retard the open ing of said switch and springs mounted on said levers urging said pawls toward said cams.

10. In a device of the character described, a

plurality of levers each carrying a roller on one side and two pawls on the other side thereof, a shaft located transversely to said levers, two cams carried by said shaft for each lever, one of said cams being adapted to strike said pawls and the other one having a rounded end to strike said roller, and a motor to drive said cams and springs mounted on said levers urging said pawls toward said cams.

11. In a device of the character described, a plurality of levers each carrying a roller on one side and two pawls on the other side thereof, a

-shaft located transversely to said levers, two

cams carried by said shaft for eachlever, one of said cams being adapted to strike said pawls and the other one having a rounded end to strike said roller, a motor to drive said cams and a reversing switch for said motor and springs mounted on said levers urging said pawls toward said cams.

12. In a device of the character described, a plurality of levers each carrying a roller on one side-and two pawls on the other side thereof, a

lshaft located transversely to said levers, two

cams carried by said shaft for each lever, one of said cams being adapted to strike said pawls and the other one having a rounded end to strike said roller, a motor to drive said cams and a reversing switch for said motor operated by said shaft within one revolution of said shaft and springs mounted on said levers urging said pawls toward said cams.

PAUL WARE.

HERBERT BERNARD.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 503,420 Johnson et al Aug. l5, 1893 937,844 McKeen Oct. 26, 1909 1,022,708 Smith Apr. 9, 1912 1,490,328 Knutson Apr.'l5, 1924 1,728,186 Moore Sept. 17, 1929 2,320,628 Mahnken June l, 1943 FOREIGN PATENTS Number Country Date 97,212 Austria June l0, 1924 

